Changes in the health care system make it necessary to regularly update our knowledge of how services for drug use disorders are provided. It is particularly important in the current environment because of the recent passage of federal parity legislation which requires group health plans offering mental health/addiction services to cover these services in a comparable manner to medical/ surgical services, effective January 1, 2010 for most health plans. Building on two previous rounds of our health plan survey, we propose to (1) enhance the core third round planned for 2010 by adding specific questions on drug abuse treatment and an in-depth module on parity, and (2) conduct a follow-up survey in 2012 focused on health plan response after final parity regulations have been issued and the 2011 cost opt-out provision is finished. The specific aims are: * Describe the provision of services for drug use disorders in private health plans in terms of administrative and clinical factors by enhancing a survey for benefit year 2010 to specifically focus on drug abuse services and analyze changes in health plans' provision of these services in the last decade by comparing to previous rounds of the survey in 1999 and 2003. * Study health plans' specific responses to the implementation of federal parity legislation on January 1, 2010 with an in-depth analysis of changes that were specifically adopted because of parity, by enhancing the 2010 survey through a special module on parity. * Study health plans' further responses to federal parity legislation in benefit year 2012, following both the requirement that all plans opting out in 2011 participate in 2012 and the issuance of clarifying final regulations expected to go into effect in 2011. * Model changes from benefit year 2010 to 2012 in health plans' implementation of parity, reflecting changes in response to parity regulations and the cost opt-out provision. The proposed study of drug treatment services will combine the 1999, 2003, and the 2010 rounds and the 2012 parity follow-up of our nationally representative health plan survey in a prospective design that will allow us to track how the delivery of drug services evolves within the changing health care market. It will specifically focus on issues related to federal parity, particularly health plan response in light of regulations and cost opt- out provisions.